Additive compositions for paper manufacturing

Description

1 / 44 “ADDITIVE COMPOSITIONS FOR PAPER MANUFACTURING” DESCRIPTION FIELD

[0001] This description generally refers to additive compounds and compositions for papermaking and, more specifically, to performance and process additives using combinations of glyoxylated cationic polyacrylamides and anionic polyacrylamides and methods for manufacturing and using them. BACKGROUND

[0002] Papermaking is a complex process in which paper is prepared from pulp (e.g., wood), water, filler, and various chemicals. Papermaking is among the most water-intensive industries, as the processes include numerous stages dependent on substantial amounts of water and aqueous solutions being added to the cellulosic fibers (i.e., the “inlet stream”) to give a feed and eventually separated from the feed (i.e., the “effluent stream”) to give the final product. In the course of a typical papermaking process, a relatively concentrated aqueous flow pulp of cellulosic material (i.e., “thick stock”) is diluted by the addition of water to give a relatively dilute flow pulp of cellulosic material (i.e., “thin stock”), which is used to prepare a paper web that must be dewatered to give the final product.Throughout the papermaking process, various chemical additives are used to improve particular properties of the process (i.e., “process aids”) and / or the final product being prepared (i.e., “functional aids”). Examples of process aids include defoamers and antifoaming agents, retention aids, biocides, drainage aids, forming aids, etc. Examples of functional additives include strength aids, for example, to impart temporary wet strength (TWS), wet strength (WS), and / or dry strength (DS) to the final product.

[0003] In view of the number and complexity of stages required in a given paper manufacturing process and the number and quantities of additives used in each stage, there is a growing demand for additives that provide improvements Petition 870250109957, dated 01 / 12 / 2025, page 7 / 50 2 / 44 both process and functional to a given process. Unfortunately, however, achieving some demand after improvements can lead to a decrease in other performance factors. For example, achieving high retention, which can lead to improvements in the strength of the final product, can lead to reduced drainage and formation. Using conventional high molecular weight drainage aids can provide excellent drainage and retention, but offers little to no strength benefit and in some cases results in reduced strength due to excessive flocculation. Certain DS aids such as polyamidoepichlorohydrins (PAE) can give excellent dry strength, but offer little to no drainage benefit and have limited repulpability.To further complicate matters, the efficiency of any given solution is heavily dependent on feed, with some of the best known dry strengths and / or drainage aids falling short of desired conditions, for example, due to fines content, lignin content and / or conductivity of the feeding system. As such, while programs exist to address these feed-derived performance reductions, there is still a need for additives that provide exceptional dewatering and good dry strength even in the most challenging feeding systems.

[0004] A category of chemicals being increasingly explored for multi-purpose additive application includes glyoxylated polyacrylamide (GPAM) resins, which have been used in the paper industry for many years as process aids, for example, to improve water drainage during the papermaking process, and also as functional additives, for example, to impart temporary wet strength (TWS), wet strength (WS), and dry strength (DS) to the final paper(s) being prepared. Typical GPAM resins are prepared by glyoxalylation of polyacrylamides (PAM), i.e., reacting glyoxal with a PAM or PAM copolymer, such as those prepared from acrylamide (AM) and various anionic or cationic monomers. As just one example, diallyldimethylammonium chloride (DADMAC) is a cationic monomer used to prepare poly(AM / DADMAC) copolymers, which can be used Petition 870250109957, dated 01 / 12 / 2025, page 8 / 50 3 / 44 as a prepolymer in a glyoxylation reaction to give the corresponding GPAM resins (i.e., glyoxylated poly(AM / DADMAC)). Unfortunately, conventional GPAM resins suffer from numerous disadvantages associated with production, storage, and use. For example, while many commercial GPAM resins are known to act as exceptional strength aids, such resins typically perform poorly in difficult feeds, especially with respect to dewatering and drainage.

[0005] Anionic polyacrylamides (APAMs) can also be used as resistance aids. However, due to the net charge, the use of a cationic cofactor is typically required for APAM retention. Furthermore, although the use of APAM may also allow higher dosing of certain cationic resistance aids (e.g., with low charge demand feeds), APAM generally has a negative and often severe effect on drainage. BRIEF SUMMARY

[0006] An optimized additive composition for drainage in papermaking is provided. The additive composition comprises an aqueous medium and a glyoxylated polyacrylamide (GPAM) resin having a weighted average molecular weight (Mw) of at least about 5 MDa and a cationic monomer content of at least about 4 mol%, alternatively at least about 10 mol%. The additive composition also comprises an anionic polyacrylamide (APAM) resin having an Mw of at least about 0.25 MDa and an anionic monomer content of up to about 25 mol%. The additive composition comprises the APAM resin and the GPAM resin in a w / w ratio of about 1:99 to about 1:2 (APAM:GPAM), based on the total weight of the APAM resin and the GPAM resin. GPAM resin can be prepared in situ during a papermaking process (i.e., as an on-site GPAM resin).

[0007] A method for preparing the additive composition (the “preparation method”) is also provided and comprises preparing a cationic acrylamide (CPAM) prepolymer and selectively glyoxalating the CPAM prepolymer in Petition 870250109957, dated 01 / 12 / 2025, page 9 / 50 4 / 44 aqueous medium to give the GPAM resin. The CPAM prepolymer has a predetermined cationic monomer content and selectively glyoxalating the CPAM prepolymer comprises controlling the concentration of the CPAM prepolymer in the aqueous medium during glyoxalation to give GPAM with a relatively high Mw. The preparation method further comprises combining APAM resin and GPAM resin in a w / w ratio of about 1:99 to about 1:2 (APAM:GPAM), thereby giving the additive composition. The preparation method can be carried out in situ during a papermaking process (i.e., as an on-site method).

[0008] A process for forming paper with the additive composition (the “process”) is also provided. The process comprises, as basic steps, providing an aqueous suspension of cellulosic fibers, forming the cellulosic fibers into a sheet and drying the sheet to produce paper. The process also comprises combining the additive composition with the cellulosic fibers in the aqueous suspension (e.g., wet-end addition and / or in situ preparation) or applying the additive composition to the sheet once formed. DETAILED DESCRIPTION

[0009] The following detailed description is merely exemplary in nature and is not intended to limit the present composition or method. Furthermore, there is no intention to be bound by any theory presented in the preceding background or in the following detailed description. Conventional techniques relating to the compositions, methods, processes, and portions thereof presented herein in the embodiments may not be described in detail for the sake of brevity. Several matters and process steps described herein may be incorporated into a more comprehensive procedure or process having additional steps or functionalities not described herein in detail because they are well known and easily assessed by those skilled in the art. As such, in the interest of brevity, such conventional steps may be mentioned only briefly or will be omitted entirely without providing well-known process details. Petition 870250109957, dated 01 / 12 / 2025, page 10 / 50 5 / 44

[0010] An optimized additive composition for drainage is provided, along with a method for preparing and processes for implementing and using it. The additive composition is useful in providing a functionalized polymer composition to production processes in order to provide process and / or product improvements based on the properties of the functionalized polymers.

[0011] Specifically, the additive composition comprises a glyoxylated polyacrylamide (GPAM) resin having a high molecular weight and high cationic charge, which provides excellent drainage for difficult feeds and good dry strength to the products, and thus the additive composition can be used in papermaking processes to provide improvements and advantages to the same. The additive composition also comprises an anionic polyacrylamide (APAM) resin, which also provides good dry strength to the products and may also allow higher dosage of cationic strength enhancers.

[0012] As described and demonstrated herein in the embodiments and examples, the specific combinations of APAM and GPAM resins particular to the additive composition exhibit improved functionality and performance by providing enhanced strength, without the disadvantages or deficiencies associated with the conventional application of APAM-based additives. Furthermore, the utility and adjustability of the additive composition allows for increased use cases, providing a flexible yet effective system for balancing strength and drainage properties for improved machine and product efficiency.

[0013] The additive composition comprises an aqueous medium. The aqueous medium is not particularly limited and may alternatively comprise any aqueous composition compatible with GPAM resin, APAM resin and / or the components used to prepare them, as well as APAM resins. Thus, the aqueous medium may be a water-based solution or suspension, optionally including additional components such as process water from a papermaking operation or simply an aqueous carrier vehicle used in the preparation of GPAM resin, as described below.

[0014] Typically, the additive composition comprises GPAM resin in the medium Petition 870250109957, dated 01 / 12 / 2025, page 11 / 50 6 / 44 aqueous in a functional quantity, that is, in a solids content that maximizes the amount of GPAM resin while maintaining a useful flowable state of the composition. In this sense, the GPAM resin may be present in an amount of more than 0% by weight less than the gel point of the GPAM resin in the aqueous medium. In some embodiments, the GPAM resin is present in an amount of about 1.2 to about 6%, such as about 1.2 to about 5%, alternatively about 1.3 to about 4%, alternatively about 1.4 to about 3%, alternatively about 1.95 to about 2.45% based on the aqueous medium (i.e., as % solids). However, as will be evaluated from the method below, the amount of GPAM present in the composition may be dependent on the amount of prepolymer used in the method.

[0015] GPAM resin typically has a Mw of at least about 5 megadaltons (MDa). In certain embodiments, GPAM resin has an Mw of at least about 6 MDa, alternatively at least about 6.5, alternatively at least about 7, alternatively at least about 7.5 MDa. The Mw range is not particularly limited above the bottom values ​​of these quoted ranges (i.e., about 5 MDa or above, alternatively about 5.5 MDa or above, etc.). As such, GPAM resin may have an Mw in the range of 5 to 50 MDa, such as 5 to 40, alternatively 5 to 35, alternatively 5 to 30 MDa. In specific embodiments, GPAM resin may have a higher Mw than those listed in the aforementioned ranges. Such GPAM resins can be obtained and provide the additive composition benefits described herein.The particular Mw can be selected by a person skilled in the art in view of the embodiments shown and described herein, for example, in view of a desired use or particular application of the additive composition being targeted.

[0016] GPAM resin can be obtained or prepared. Typically, however, GPAM resin is prepared at the site of use (e.g., as an “on-site” method), which will be understood by those skilled in the art. The particular properties and traits of GPAM resin, including those introduced above, will be evaluated in view of the method and components used in the relevant steps of the method. Petition 870250109957, dated 01 / 12 / 2025, page 12 / 50 7 / 44 preparation presented here.

[0017] In general, GPAM resin is prepared in an aqueous medium or in another aqueous medium that is formulated in the final additive composition. As such, the preparation of GPAM resin described here in detail can be used in addition to or in place of conventional processes known in the art.

[0018] Preparing GPAM resin involves glyoxalating a cationic acrylamide prepolymer (CPAM), as described below.

[0019] The CPAM prepolymer can be prepared or obtained. In some embodiments, the method comprises preparing the CPAM prepolymer. For example, the preparation may comprise reacting an acrylamide monomer (AM), a cationic monomer and optionally one or more additional ethylenically unsaturated monomers, in the presence of a chain transfer agent. However, there are multiple methods for preparing the CPAM prepolymer, which are known in the art and can be adapted from conventional methods for preparing prepolymers suitable for glyoxation to give a GPAM resin. Examples include free radical polymerization in water, such as by using a redox initiator system (e.g., sodium metabisulfite and sodium persulfate).Other combinations of redox initiator systems to initiate the polymerization of suitable comonomers can also be used, including other persulfate salts such as potassium persulfate or ammonium persulfate or other components such as potassium bromate. Such redox initiator systems can be used in combination with a chain transfer agent, such as a chain transfer agent based on sodium hypophosphite, sodium formate, isopropanol or mercapto compounds.

[0020] The CPAM prepolymer typically includes ionic repeating units, for example, cationic repeating units derived from the cationic monomer. The cationic comonomer can be any cationic monomer capable of reacting via chain radical polymerization with the AM monomer and / or other monomers / comonomers to form the CPAM prepolymer.

[0021] Examples of cationic monomers include diallyl amino derivatives Petition 870250109957, dated 01 / 12 / 2025, p. 13 / 50 8 / 44 tertiary and quaternary or tertiary and quaternary amino acid derivatives of acrylic acid or (meth)acrylic acid or acrylamide or (meth)acrylamide, vinylpyridines and quaternary vinylpyridines or parastyrene derivatives containing tertiary or quaternary amino acid derivatives. Cationic comonomers may be selected from diallyldimethylammonium chloride (DADMAC), [2-(acrylamido)ethyl]trimethylammonium chloride, [2-(methacrylamido)ethyl]trimethylammonium chloride, [3-(acrylamido)propyl]trimethylammonium chloride, [3-(methacrylamido)propyl]trimethylammonium chloride, N-methyl-2-vinylpyridinium N-methyl-4-vinylpyridinium, p-vinylphenyltrimethylammonium chloride, p-vinylbenzyltrimethylammonium chloride, [2-(acryloyloxy)ethyl]trimethylammonium chloride, [2-(methacryloyloxy)ethyl]trimethylammonium chloride, [3-(acryloyloxy)propyl]trimethylammonium chloride, [3-(methacryloyloxy)propyl]trimethylammonium chloride and combinations thereof.It is understood that mixtures of cationic comonomers can be used for the same purposes. In some embodiments, the cationic monomer includes diallyldimethylammonium chloride (DADMAC).

[0022] The CPAM prepolymer may contain other monomer units provided by additional ethylenically unsaturated monomers in the polymerization. These monomers are typically selected not to significantly interfere with the glyoxylation process. For example, additional monomer units may be acrylates or alkyl acrylates (e.g., methacrylates, methyl methacrylate, etc.), styrene, vinyl acetates, or alkyl acrylates.

[0023] Polymerization is typically carried out in an aqueous solution (e.g., in an aqueous medium) at a temperature of at least about 50°C. It is sometimes advantageous to raise the temperature after the addition of all comonomers has been completed in order to reduce the level of residual monomers in the product. The pH during the reaction can be adjusted with acids or bases or with a buffer and may be dependent on the initiator system and components used in the reaction.

[0024] Comonomers can be added all at once or added over any period of time. If one monomer is less reactive than another, then it is advantageous to add part or all of the monomer. Petition 870250109957, dated 01 / 12 / 2025, page 14 / 50 9 / 44 which reacts more slowly at the beginning of polymerization, followed by a slow addition to continuous or multiple portions of the most reactive monomer. Adjusting feed rates can lead to more uniformity of polymer chain compositions. Similarly, initiators can be added all at once or added over any period of time. To reduce the amount of residual monomer in the copolymer, it is often advantageous to continue adding the initiator system for some time after all monomers have been added or to introduce additional amounts of initiator to batches. Controlling compositional uniformity and polymer molecular weight by controlling additional times is well known in the polymer industry.

[0025] In general, CPAM prepolymer is prepared with a predetermined cationic monomer content (i.e., mol %). For example, CPAM prepolymer typically comprises at least about 4 mol %, alternatively at least about 10, alternatively at least about 12, alternatively at least about 15, alternatively at least about 20 mol % of cationic monomer content (i.e., units derived from the cationic monomer). In some embodiments, CPAM prepolymer comprises from about 12 to about 50, alternatively from about 15 to about 45, alternatively from about 18 to about 40, alternatively from about 20 to about 40 mol % of cationic monomer units. In specific embodiments, the CPAM prepolymer comprises from about 15 to about 30, alternatively from about 20 to about 30, alternatively from about 20 to about 25 mol%, of cationic monomer units.However, it will be assessed from the description here that the particular cationic monomer content of the CPAM prepolymer, and thus of the GPAM resin, can be independently selected based on a desired use. For example, a lower cationic content can be selected for use in difficult feeds, i.e., with higher lignin content, anionic waste, etc. However, the combination of APAM resin and GPAM resin of the present embodiments may also allow selection with respect to increased cationic monomer content. Petition 870250109957, dated 01 / 12 / 2025, page 15 / 50 10 / 44

[0026] As introduced above, GPAM resin is prepared by glyoxylation of a CPAM prepolymer, i.e., reacting the CPAM prepolymer with glyoxal or a suitable derivative (e.g., glyoxylic acid or a similar functionalizing agent) to prepare a GPAM resin therefrom. As such, a method for preparing GPAM resin is provided and includes glyoxylating CPAM (e.g., as a prepolymer) to give a GPAM resin therefrom. The method can be used to selectively glyoxate the CPAM prepolymer by controlling the concentration of CPAM prepolymer in an aqueous medium during glyoxylation. In this way, GPAM resins having high Mw can be prepared, optionally decoupled from the Mw of the CPAM used as the prepolymer being glyoxated. The Mw of CPAM can be determined using relative SEC against known standards or using other techniques known in the art. The Mw of GPAM can be determined by MALS, AF4 MALS, SEC MALS, etc. batches.or using other techniques known in the art.

[0027] As understood in the art, the reaction of the CPAM prepolymer with glyoxal can be carried out under varying conditions of time, temperature, pH, etc. Typically, glyoxal is rapidly added to the CPAM prepolymer to minimize crosslinking. Alternatively, the CPAM prepolymer can be added to the glyoxal. It is also generally understood in the art that the molecular weight of the CPAM prepolymer and the ratio of glyoxal to acrylamide groups in the CPAM prepolymer (including any of these from the cationic monomer) can be adjusted to achieve desired levels of crosslinking and viscosity built up during a glyoxation process.

[0028] CPAM prepolymer and glyoxal are typically reacted in a dry weight (w / w) ratio of about 75:25 to about 95:5, such as from about 80:20 to about 90:10. In specific embodiments, a dry weight ratio of 85:15 is targeted. In other embodiments, a higher glyoxal content is used, such as at a ratio of about 85:30 (w / w).

[0029] It is typically preferred to conduct the glyoxation reaction at a higher concentration (i.e., % solids) of CPAM to optimize efficient use. Petition 870250109957, dated 01 / 12 / 2025, p. 16 / 50 11 / 44 of the reaction vessel and / or to obtain a final product with a higher GPAM concentration. Meanwhile, particular conditions will be selected to control the GPAM properties (e.g., MW, Rg, etc.) and / or GPAM composition (e.g., viscosity, etc.), which will include the degree of intermolecular crosslinking, as described herein.

[0030] In some embodiments, the glyoxation reaction specifically involves monitoring and selectively controlling the solids content of the reaction, in terms of the GPAM product. In other words, in such embodiments, the progress of the reaction can be monitored and the amount of GPAM that is prepared can be controlled. In this embodiment, glyoxation can be carried out as a “low solids” process or a “high solids” process, for example, depending on the desired use and / or application of the GPAM that is prepared. For example, when carrying out the glyoxation reaction on-site, as described in more detail below, glyoxation is typically carried out as a low solids process. When glyoxation is carried out off-site, for example, before subsequent storage and / or shipment(s), a high solids process may be favored (e.g., to reduce storage, transport, etc. economies).In general, those skilled in the art will understand that a “low solids” process, in the context of glyoxalation, is any process where a significant viscosity buildup is not observed (i.e., a low solids process can be run virtually indefinitely and not form a gel). Conversely, a “high solids” process in this same context is a process where a significant viscosity buildup is observed and, if not quenched, will eventually reach a gel point. Therefore, it should be assessed that the cutoff between high solids and low solids processes becomes dynamic and related to the identity and characteristics of the reaction components (e.g., Mw of CPAM, CPAM to glyoxal ratio, etc.). The solids value at which a process moves between a high and low solids process can be understood as the “critical concentration” of a given reaction.Consequently, it should be evaluated that glyoxation can be performed at high or low solids content, on-site or off-site, with different processes. Petition 870250109957, dated 01 / 12 / 2025, page 17 / 50 12 / 44 particulars selected by those skilled in the art. Parameters and properties of such process variations are presented here, but may be modified, supplemented and / or replaced by other glyoxation techniques known in the art. Such processes may be selected based on a desired property of the GPAM resin (e.g., Mw, viscosity, Rg, filler density, zeta potential, etc.) and / or additive composition (e.g., solids content, viscosity, etc.) being prepared or a particular use thereof.

[0031] Monitoring the reaction progression is not limited to any particular technique, but rather can be carried out using any known method applicable to the selected reaction conditions. For example, the reaction can be monitored according to a property directly related to the solids content of the prepared GPAM, such as the turbidity, viscosity, pH and / or reaction temperature. Similarly, the reaction can be monitored according to a property indirectly related to the solids content, i.e., a property useful for monitoring the glyoxation reaction, such as the current consumption of a circulation pump, stirrer, etc., influenced by the reaction viscosity. It is generally known that the reaction mixture will increase in viscosity as the GPAM is being prepared.Any of these properties can be monitored over time, for example, as a difference measurement, and multiple properties can be monitored in tandem for precise value determination and control.

[0032] The concentration of CPAM can be selectively controlled to alter the Mw of the prepared GPAM resin. For example, in some embodiments, CPAM is present in the aqueous medium at an initial concentration of about 0.9 to about 5.7%, alternatively from about 1.5 to about 2.3%. This concentration is typically defined in terms of solids, i.e., the percent weight concentration of the starting CPAM at the beginning of the glyoxation reaction, i.e., when all the glyoxal has been added. Overall, these ranges are implemented for a low solids process, as introduced above. In such embodiments, the GPAM resin can be prepared in the aqueous medium at a solids content (%) of about A + B, Petition 870250109957, dated 01 / 12 / 2025, page 18 / 50 13 / 44 where A is the initial concentration of CPAM in the aqueous medium used in glyoxylation and B is a conversion factor based on one or more of the predetermined physical properties of CPAM or a parameter of the glyoxylation reaction itself. In this way, the solids content of CPAM and the solids content of GPAM resin can be described in relation to each other. Similarly, selective glyoxylation can be understood to include selecting a desired CPAM concentration based on a desired solids content of GPAM resin in the additive composition.

[0033] GPAM resins can be adjusted to a pH of about 3 after the glyoxation reaction to improve storage stability until they are used or can be used directly without further adjustments.

[0034] APAM resin can be prepared or obtained. In some embodiments, the method comprises preparing the APAM resin. For example, the preparation may comprise reacting an acrylamide (AM) monomer, an anionic monomer and optionally one or more additional ethylenically unsaturated monomers.

[0035] Examples of anionic monomers generally include α,β-unsaturated carboxylic acids having 3 to 5 carbon atoms and salts thereof. Examples include acrylic acid, methacrylic acid, itaconic acid, etc., and salts thereof. Acrylic acid and itaconic acid are typically preferred and can be used as sodium or other salt forms.

[0036] Optionally, a crosslinking agent (e.g., a divinyl monomer) is used. In addition, quantities of cationic monomers may also be used, as understood in the art. However, the use of cationic monomers will typically be minimized due to the charge balance of the systems in which the additive composition is typically used.

[0037] In general, there are multiple methods for preparing APAM resin, which are known in the art and can be adapted from conventional methods for preparing anionic resins suitable for use herein. Examples include free-radical polymerization, for example, using a redox initiator system. Other methods include addition polymerization, anionic polymerization, solution emulsion polymerization, etc. Typically, the Petition 870250109957, dated 01 / 12 / 2025, page 19 / 50 14 / 44 free radical polymerization is used.

[0038] APAM resin is selected or prepared with a predetermined anionic monomer content (i.e., mol%). For example, APAM resin typically comprises an anionic monomer content of about 25 mol% or less, such as from about 0.1 mol% to about 25 mol%, depending on the GPAM used. In some embodiments, the anionic monomer content of the APAM resin is less than about 25, alternatively less than about 20, alternatively less than about 15, alternatively less than about 12, alternatively less than about 10, alternatively less than about 8, alternatively less than about 6 mol%. However, it will be assessed from the description herein that the anionic monomer content of the particular APAM resin can be independently selected based on a desired use, i.e., as optimized according to the embodiments herein.For example, lower anion content may be selected for use in certain feeds, for example, with higher lignin content, anionic waste, etc. Alternatively, higher anion content may be used to further balance the GPAM load. Overall, the combination of APAM resin and GPAM resin of the present embodiments may allow the selection of increased cationic monomer content and thus compensate for certain deficiencies frequently associated with typical APAM resins with higher anion content.

[0039] APAM resin typically has a Mw of at least about 0.25 megadaltons (MDa). In certain embodiments, APAM resin has an Mw of at least about 0.5 MDa, alternatively at least about 0.75, alternatively at least about 1, alternatively at least about 1.5 MDa. The Mw range is not particularly limited, but it is impactful for the adjustability of the additive composition, as shown in the examples. As such, APAM resin may have an Mw in the range of about 0.25 to about 5 MDa for example, such as from about 0.5 to about 4, alternatively from about 0.5 to about 3 MDa. In specific embodiments, APAM resin may have a higher Mw than those listed in the aforementioned ranges. Such APAM resins may be Petition 870250109957, dated 01 / 12 / 2025, p. 20 / 50 15 / 44 obtained and provide the benefits of the additive composition described herein. The particular Mw may be selected by a person skilled in the art in view of the embodiments shown and described herein, for example, in view of a desired use or particular application of the additive composition that is targeted. The weighted average molecular weight of the APAM resin may be determined by any suitable technique, such as size exclusion chromatography (SEC) or other methods described herein.

[0040] In general, the additive composition comprises APAM resin and GPAM resin in a w / w ratio of about 1:99 to about 1:2 (APAM:GPAM), that is, a ratio based on the total weight of APAM resin and GPAM used. In this way, although almost equal quantities of the two resins can be used, APAM resin is typically used in relatively smaller quantities (proportion) compared to GPAM resin. The effects of the reduced APAM resin load are shown in the examples herein, which demonstrate the adjustability of the additive composition in terms of the Mw of GPAM resin, the cationic monomer content of GPAM resin, the Mw of APAM resin, and the anionic monomer content of APAM resin. In specific embodiments, the additive composition comprises APAM resin and GPAM resin in a w / w ratio of about 1:30 to about 1:3, alternatively from about 1:20 to about 1:5, alternatively from about 1:15 to about 1:7, alternatively from about 1:12 to about 1:7 (APAM:GPAM).In some embodiments, the relative proportion of APAM used is consistent across all dosages of a given application, and the total dosage of the additive composition is altered to provide the desired effect. For example, in some embodiments a w / w ratio of about 1:8 to about 1:10 (APAM:GPAM) is used.

[0041] The additive composition can be used to manufacture paper, comprising pulp and the resins APAM and GPAM. The additive composition used in papermaking can lead to beneficial properties, such as, for example, improved dry strength, temporary wet strength, permanent wet strength, decline in wet strength, etc., compared with the same properties when a conventional additive composition (e.g., a Petition 870250109957, dated 01 / 12 / 2025, page 21 / 50 16 / 44 GPAM resin (relatively low Mw) is used, as well as process improvements such as increased drainage rate compared to conventional additives (e.g., APAM resins combined with conventional GPAM resins, etc.).

[0042] The additive composition can be formulated as a single composition (i.e., an aqueous composition comprising both APAM and GPAM resin). However, GPAM resin is typically prepared in / as an aqueous composition, as described above, which can be combined with APAM or used separately. For example, the composition may comprise APAM and GPAM resins as separate packing components, which can be applied (e.g., to pulp, sheets, etc.) separately, sequentially, or simultaneously.

[0043] In certain embodiments, the additive composition comprises GPAM resin as an aqueous composition obtained directly from the glyoxation method presented herein, which can be added to / combined with a component comprising APAM resin or instead used directly (e.g., in combination with the use of a separate component containing APAM). In this way, as described in further detail herein, glyoxation can be carried out in advance of a desired time of use of the additive composition (i.e., “off site”) or instead it can be carried out substantially at the same time that the additive composition is to be used (i.e., “on site”). The time between the formation of the GPAM resin, its reactive window, the GPAM content in the additive composition and other factors known in the art will all be used to inform the practical limits of the concentration of a particular GPAM resin in the additive composition of the present embodiments.

[0044] In some embodiments, the method comprises applying the APAM resin to an aqueous suspension of cellulosic fibers (e.g., pulp) directly, separate from the GPAM resin. In such embodiments, combining the APAM resin and the GPAM resin may comprise providing the GPAM resin to the aqueous suspension of cellulosic fibers, for example, before or after the APAM resin is applied to it. Petition 870250109957, dated 01 / 12 / 2025, page 22 / 50 17 / 44 In specific applications, it has been shown that applying APAM resin before GPAM resin provides superior results in terms of drainage and / or improved strength. The parameters and scope of these improvements are described in more detail below.

[0045] The additive composition can be prepared and subsequently combined with a pre-formed aqueous suspension of cellulosic fibers. For example, GPAM resin can be prepared and introduced into the suspension within a suitable storage time, such as within about 10, alternatively about 8, or alternatively about 5 hours after glyoxylation. Alternatively, the additive composition can be prepared in aqueous suspension, i.e., where GPAM resin is prepared in situ with the aqueous suspension. Such processes are known in the art as “on-site” processes and are particularly suitable for use in the present embodiments. In each such case, APAM resin is typically introduced before GPAM resin as described herein.

[0046] The papermaking process involves multiple steps, generally including: forming an aqueous suspension of cellulosic fibers; adding additives (e.g., additive composition) to the suspension; forming a sheet from the fibers; and drying the sheet to give the paper. Additional steps may also be used (e.g., for woven and towel grades, a fourth step of creping or forming a paper structure to provide properties such as softness is typically used). These steps and variations of the process are known to those skilled in the art.

[0047] It will be assessed that the application of the additive composition to the aqueous suspension of cellulosic fibers is typically carried out as an addition in the wet end, for example, to treat a stock mixture prepared after pulping. The particular type of pulp, that is, the particular types of cellulosic material to be treated, is not limited, but may alter the particular performance characteristics of a given APM / GPAM combination. However, such alterations are not outside the scope of the present embodiments, but rather Petition 870250109957, dated 01 / 12 / 2025, p. 23 / 50 18 / 44 are considered here since the additive composition can be adjusted to optimize performance (e.g., strength, drainage) in numerous compositions from virgin to recycled fiber, as will be readily understood by those skilled in the art in view of the examples herein.

[0048] It is also understood that the additive composition may be applied in other process steps, such as by spray application to the sheet, between layers of a multi-layer product, etc. Such applications will be understood by those skilled in the art and may be modified for use with the additive composition. Alternatively, the additive composition may be formulated or otherwise altered for use in a specific application and / or with particular equipment.

[0049] In view of the above, a process for forming paper is also provided here. The process generally comprises: (1) to provide an aqueous suspension of cellulosic fibers; (2) combine the additive composition with the aqueous suspension: (3) forming the cellulosic fibers into a sheet; and (4) drying the sheet to produce paper.

[0050] In such embodiments, combining the additive composition with the aqueous suspension typically comprises first providing the anionic polyacrylamide resin (APAM) to the aqueous suspension and then providing the glyoxylated polyacrylamide resin (GPAM) to the aqueous suspension.

[0051] In other embodiments, the process for forming paper comprised (1) providing an aqueous suspension of cellulosic fibers; (2) to form the cellulosic fibers in a sheet; (3) applying an additive composition comprising an anionic polyacrylamide resin (APAM) and a glyoxylated polyacrylamide resin (GPAM) to a sheet surface; and (4) drying the sheet to produce a paper.

[0052] In such embodiments, APAM and GPAM resins may be applied together or separately and sequentially or substantially at the same time. Petition 870250109957, dated 01 / 12 / 2025, page 24 / 50 19 / 44 (for example, using two applicators).

[0053] As demonstrated below, the additive composition provides improved strength and maintained or improved drainage characteristics compared to conventional compositions using similar components. Specifically, as provided herein, the embodiments allow for optimization of the relative APAM:GPAM ratio, and the additive composition provides a significant improvement in strength on an equal total dosage basis compared to the use of a conventional GPAM resin alone. Additionally, although drainage is usually negatively impacted by the use of APAM, the specific combinations of the present embodiments allowed drainage performance to be maintained compared to the comparative use of GPAM alone.

[0054] In particular implementations, the additive composition provides dry strength to the paper that is formed. For example, in some embodiments, the paper exhibits a mechanical strength performance (e.g., as determined by the ring crush test (e.g., TAPPI T822)) that is increased by at least about 1, alternatively at least about 3, alternatively at least about 6, alternatively at least about 9%, compared to a paper prepared with a substantially similar process that is substantially free of the additive composition or use of components outside the scope of the present embodiments.

[0055] In addition to increased strength, the additive composition can provide an improved drainage rate, for example, as exhibited during sheet formation. In certain embodiments, the additive composition provides a drainage time reduced by at least about 10, alternatively at least about 20, alternatively at least about 25, alternatively at least about 30%, compared with a drainage rate of a substantially similar process that is completely free of the additive composition. Similarly, the additive composition can exhibit a drainage time reduced by at least about 15, alternatively at least about 20%, alternatively at least about 25%, compared with a drainage rate of a process Petition 870250109957, dated 01 / 12 / 2025, page 25 / 50 20 / 44 substantially similar that is free of the GPAM resin additive composition.

[0056] The papermaking process introduced above may additionally comprise steps of drying, patterning, treatment and creping of the paper to form a finished paper product. Finished paper products may include, but are not limited to, toilet paper, facial tissues and paper towels, which are also considered herein. EXAMPLES

[0057] The following examples, illustrating embodiments of this description, are intended to illustrate and not limit the invention. Unless otherwise stated, all solvents, substrates and reagents are purchased or otherwise obtained from various commercial suppliers (e.g., SigmaAldrich, VWR, Alfa Aesar) and used as received (i.e., without further purification) or in a form conventionally used in the art.

[0058] General Synthesis of Cationic Acrylamide Prepolymer (CPAM)

[0059] A reaction flask is loaded with DI water, diallyldimethylammonium chloride (DADMAC), a pH modifier, and a chain transfer agent. Two external feeds are connected to the reaction flask, one containing acrylamide, the other containing sodium metabisulfite (SMBS) and chain transfer reagent. The reaction mixture is heated to 35°C, then ammonium persulfate (APS) and sodium bromate are added, followed by the start of the feeds. The acrylamide feed is set to be added at 135 minutes, the SMBS feed is set to be added at 195 minutes. During the acrylamide feed, the reaction is gradually heated by an external heat source at ~0.4°C / min up to 90°C. After the acrylamide feed is complete, a second portion of APS is added and the reaction is maintained at 90°C for one hour.The amount of DADMAC is varied as needed to manufacture a prepolymer with the desired amount of cationic monomer. The molecular weight (Mw) of the prepolymer is manipulated by increasing or decreasing the amount of chain transfer agent as needed. The Mw of CPAM is determined using known methods, such as... Petition 870250109957, dated 01 / 12 / 2025, page 26 / 50 21 / 44 as per SEC regarding against known standards. General Glyoxation Procedure: GPAM Synthesis

[0060] A CPAM prepolymer is charged into a reaction flask and diluted with DI water so that the polymer concentration is as desired, to which glyoxal is added in a dry w / w ratio of 15:85 relative to the prepolymer. The pH is raised to 10.2 using dilute NaOH and this pH is maintained for the desired reaction time. After which, the reaction is quenched by reducing the pH to 4 with dilute sulfuric acid. The resulting glyoxal cationic polyacrylamide (GPAM) is then sorted according to known methods, such as batch MALS, SEC MALS, AF4 MALS, etc.

[0061] Although not shown in the specific examples below, glyoxation can also be carried out at a higher glyoxal ratio to alter the glyoxalation level of GPAM, such as by adding glyoxal at a dry w:w ratio of about 30:80 to the prepolymer, to give GPAM.

[0062] It will be understood that the cationic content of GPAM (e.g., reported as charge, % mol), is typically based on the % mol of the cationic monomer used to prepare the CPAM prepolymer itself. General synthesis of Anionic Polyacrylamide (APAM)

[0063] A reaction flask is charged with DI water, acrylic acid, and acrylamide. Optionally, a crosslinking agent (e.g., a divinyl monomer) is added. The pH is adjusted with sulfuric acid, and the mixture is heated to 35°C. Sodium metabisulfite (SMBS) and sodium persulfate (SPS) are added to initiate polymerization, and the temperature is allowed to rise adiabatically. The reaction is allowed to proceed for 90 min before a second amount of SMBS is added. The reaction is continued for a further 30 min. The amount of acrylic acid is varied as needed to manufacture a polymer with the desired amount of anionic monomer content. The molecular weight (Mw) of the polymer is manipulated by increasing or decreasing the amount of initiator or crosslinking agent. The APAM Mw is determined using known methods, such as by estimation from viscosity. Petition 870250109957, dated 01 / 12 / 2025, page 27 / 50 22 / 44 intrinsic (IV) against known patterns. Performance Examples

[0064] Several additive compositions are prepared using APAM and GPAM resins and analyzed. The specific parameters and properties of the APAM and GPAM resins used in the additive compositions are presented in the table below. Table 1 - Components Used Component Description Charge (% mol) Mw Range (MDa) GPAM 1 GPAM resin prepared on site 4.1%, cationic ~10 (1) GPAM 2 GPAM resin prepared on site 12.8%, cationic ~10 (1) GPAM 3 GPAM resin prepared on site 20.6%, cationic ~10 (1) GPAM 4 GPAM resin released (prefabricated) 15%, cationic ~1 to 2 (2) APAM 1 APAM polymer in solution 25%, anionic >0.5 (3) APAM 2 APAM polymer in solution 18%, anionic >0.5 (3) APAM 3 APAM polymer in granules 25%, anionic ~1 (4) APAM 4 APAM polymer in granules 10%, anionic ~2 to 3 (4) APAM 5 APAM polymer in granules 5%, anionic ~2 (4) (1) Determined by MALS (2) Determined by SEC MALS (3) Determined by SEC (4) Estimated by IV

[0065] Preparation of the Pilot Paper Machine:

[0066] A feed composed of OCC fibers was dispersed in water, refined to a CSF of 350 to 400 mL and adjusted to a pH of 7. The water used was conditioned with calcium chloride (147 g per 1000 L) and sodium bicarbonate (84 g per 1000 L) for normal hardness, and sodium sulfate was added to adjust to a Petition 870250109957, dated 01 / 12 / 2025, page 28 / 50 23 / 44 conductivity of 2000 uS / cm. 2.5% by weight (dry basis) of oxidized starch (GPC D-28F) was added to the feed. The stock was applied to the paper machine via a top headbox of the flow spreader (hydraulic) onto a flat table equipped with vacuum-assisted baffles to remove water and form a wet sheet. The wet sheet was then passed through two single-felt presses to mechanically remove water and densify the sheet. Final water removal (drying) is performed using electrically heated drying cans before being wound onto a core on the reel, targeting a base weight of 0.16 kg / m2 (100 lb / 3000 sq ft).

[0067] Mechanical strength performance: Tests A to F:

[0068] Ring crush was measured with a Crush Testing Machine, with the analysis performed according to the TAPPI T 822 method (e.g., om-16).

[0069] Five paper machine tests (Tests A to E) were conducted according to the above procedure. The specific parameters and results of the paper machine tests are shown in the tables below. All strength values ​​are reported as a% increase vs. blank, determined by the Ring Crush Test. For performance comparisons, the examples presented in each table were conducted simultaneously on the same feed. Table 2 - Paper Machine - Test A APAM GPAM Additive Composition Ex. Anionic (%) Dosage m kg / ton (lb / ton) Cationic (%) Dosage m kg / ton (lb / ton) Dosage m Total (lb / ton) APAM:GP AM Order of Add. (1a) Resistance Improvement (%)(5) A-1 N / A None 12.8 2.7 (6) 2.7 (6) 0:1 N / A 5.8 A-2 18 0.9 (2) 12.8 1.8 (4) 2.7 (6) 1:2 APA 6.9 Petition 870250109957, dated 01 / 12 / 2025, p. 29 / 50 24 / 44 M A-3 18 0.7 (1.5) 12.8 2.0 (4.5) 2.7 (6) 1:3 APA M 7.6 A-4 18 0.4 (0.86) 12.8 2.3 (5.14) 2.7 (6) 1:6 APA M 9.1 A-5 18 0.3 (0.6) 12.8 2.4 (5.4) 2.7 (6) 1:9 APA M 9.9 A-6 18 0.7 (1.5) 4.1 2.0 (4.5) 2.7 (6) 1:3 APA M 6.0 A-7 18 0.7 (1.5) 12.8 2.0 (4.5) 2.7 (6) 1:3 GPA M 11.3 A-8 10 0.7 (1.5) 12.8 2.0 (4.5) 2.7 (6) 1:3 APA M 10.4 A-9 25B 0.7 (1.5) 12.8 2.0 (4.5) 2.7 (6) 1:3 APA M 10.3 A- 10 18 0.4 (1) 12.8 2.7 (6) 3.2 (7) 1:6 APA M 11.9 A- 11 18 0.9 (2) 12.8 2.7 (6) 3.6 (8) 1:3 APA M 12.2 A- 12 N / A Nenhu ma 12.8 3.6 (8) 3.6 (8) 0:1 N / A 9.0 A- 13 N / A Nenhu ma 12.8 5.4 (12) 5.4 (12) 0:1 N / A 10.4 A- 14 18 1.4 (3) 12.8 4.1 (9) 5.4 (12) 1:3 APA M 16.2 A- 15 18 0.8 (1.7) 12.8 4.7 (10.3) 5.4 (12) 1:6 APA M 16.9 A- 16 18 0.5 (1.2) 12.8 4.9 (10.8) 5.4 (12) 1:9 FATHER M 17.9 Petition 870250109957, de 01 / 12 / 2025, p. 30 / 50 25 / 44 A- 17 18 1.4 (3) 4.1 4.1 (9) 5.4 (12) 1:3 APA M 12.1 A- 18 10 1.4 (3) 12.8 4.1 (9) 5.4 (12) 1:3 APA M 21.0

[0070] (5) Improved strength reported as % increase, relative to blank performance (Ring Crush)

[0071] B APAM 3 (granulated polymer) Table 3 - Paper Machine - Test B APAM GPAM Additive Composition Ex. Anionic (%) Dosage m kg / ton (lb / ton) Cationic (%) Dosage m kg / ton (lb / ton) Dosage m Total kg / ton (lb / ton) APAM:GP AM Order of Add. (1a) Improvement in Resistance (%)(5) B-1 N / A None 4.1 2.7 (6) 2.7 (6) 0:1 N / A 7.1 B-2 18 0.9 (2) 4.1 1.8 (4) 2.7 (6) 1:2 APA M 5.1 B-3 18 0.7 (1.5) 4.1 2.0 (4.5) 2.7 (6) 1:3 APA M 5.8 B-4 18 0.4 (0.86) 4.1 2.3 (5.14) 2.7 (6) 1:6 APA M 9.3 B-5 18 0.3 (0.6) 4.1 2.4 (5.4) 2.7 (6) 1:9 APA M 7.2 B-6 18 0.7 (1.5) 12.8 2.0 (4.5) 2.7 (6) 1:3 APA M 8.5 B-7 18 0.7 (1.5) 4.1 2.0 (4.5) 2.7 (6) 1:3 GPA M 6.2 B-8 10 0.7 4.1 2.0 2.7 (6) 1:3 APA 6.5 Petition 870250109957, dated 01 / 12 / 2025, page 31 / 50 26 / 44 (1.5) (4.5) M B-9 18 0.4 (1) 4.1 2.7 (6) 3.2 (7) 1:6 APA M 10.2 B- 10 18 0.9 (2) 4.1 2.7 (6) 3.6 (8) 1:3 APA M 7.5 B- 11 N / A None 4.1 3.6 (8) 3.6 (8) 0:1 N / A 9.2 B- 12 N / A None 4.1 5.4 (12) 5.4 (12) 0:1 N / A 13.4 B- 13 18 1.4 (3) 4.1 4.1 (9) 5.4 (12) 1:3 APA M 9.8 B- 14 18 0.8 (1.7) 4.1 4.7 (10.3) 5.4 (12) 1:6 APA M 11.0 B- 15 18 0.5 (1.2) 4.1 4.9 (10.8) 5.4 (12) 1:9 APA M 15.6 B- 16 18 1.4 (3) 12.8 4.1 (9) 5.4 (12) 1:3 APA M 13.8

[0072] (5) Improvement in resistance reported as % increase, relative to blank performance (Ring Crush) Table 4 - Paper Machine - Test C APAM GPAM Additive Composition Ex Anionic (%) Dosage m kg / ton (lb / ton) Cationic (%) Dosage m kg / ton (lb / ton) Dosage m Total kg / ton (lb / ton) APAM:GP AM Order of Add. (1a) Resistance Improvement (%)(5) C- 1 N / A None 4.1 1.8 (4) 1.8 (4) 0:1 N / A 4.3 C- N / A None 4.1 3.6 (8) 3.6 (8) 0:1 N / A 15.3 Petition 870250109957, dated 01 / 12 / 2025, page 32 / 50 27 / 44 2 ma C- 3 5 0.2 (0.4) 4.1 1.6 (3.6) 1.8 (4) 1:9 APA M 8.1 C- 4 5 0.4 (0.8) 4.1 3.3 (7.2) 3.6 (8) 1:9 APA M 11.9 C- 5 5 0.4 (0.8) 4.1 1.4 (3.2) 1.8 (4) 1:4 APA M 5.3 C- 6 5 0.7 (1.6) 4.1 2.9 (6.4) 3.6 (8) 1:4 APA M 12.3

[0073] (5) Improvement in resistance reported as % increase, relative to blank performance (Ring crush) Table 5 - Paper Machine - Test D APAM GPAM Additive Composition Ex. Anionic (%) Dosage m kg / ton (lb / ton) Cationic (%) Dosage m kg / ton (lb / ton) Dosage m Total kg / ton (lb / ton) APAM:GP AM Order of Add. (1a) Resistance Improvement (%)(5) D-1 25S 0.2 (0.4) 12.8 1.6 (3.6) 0.2 (0.4) 1:9 APA M 5.4 D-2 25S 0.4 (0.8) 12.8 3.3 (7.2) 0.4 (0.8) 1:9 APA M 12.3 D-3 N / A None 20.6 0.2 (0.4) 0.2 (0.4) 0:1 N / A 7.0 D-4 N / A None 20.6 0.4 (0.8) 0.4 (0.8) 0:1 N / A 11.1 D-5 25S 0.2 (0.4) 20.6 1.6 (3.6) 0.2 (0.4) 1:9 APA M 9.1 D-6 25S 0.4 20.6 3.3 0.4 1:9 APA 15.1 Petition 870250109957, dated 01 / 12 / 2025, page 33 / 50 28 / 44 (0.8) (7.2) (0.8) M D-7 25S 0.4 (0.8) 20.6 1.4 (3.2) 0.2 (0.4) 1:4 APA M 5.0 D-8 25S 0.7 (1.6) 20.6 2.9 (6.4) 0.4 (0.8) 1:4 APA M 11 D-9 5 0.4 (0.8) 20.6 1.4 (3.2) 0.2 (0.4) 1:4 APA M 7.5 D- 10 5 0.7 (1.6) 20.6 2.9 (6.4) 0.4 (0.8) 1:4 APA M 8.8 (5) Improved strength reported as % increase, relative to blank performance (Ring crush)

[0074] S APAM 1 (polymer in solution) Table 6 - Paper Machine - Test E APAM GPAM Additive Composition Ex. Anionic (%) Dosage m kg / ton (lb / ton) Cationic (%) Dosage m kg / ton (lb / ton) Dosage m Total kg / ton (lb / ton) APAM:GP AM Order of Add. (1a) Resistance Improvement (%)(5) E-1 N / A None 12.8 1.8 (4) 1.8 (4) 0:1 N / A 7.2 E-2 N / A None 12.8 3.6 (8) 3.6 (8) 0:1 N / A 8.8 E-3 25S 0.2 (0.4) 12.8 1.6 (3.6) 1.8 (4) 1:9 APA M 7.8 E-4 25S 0.4 (0.8) 12.8 3.3 (7.2) 3.6 (8) 1:9 APA M 10.7 E-5 5 0.2 (0.4) 12.8 1.6 (3.6) 1.8 (4) 1:9 APA M 7.5 Petition 870250109957, dated 01 / 12 / 2025, page 34 / 50 29 / 44 E-6 5 0.4 (0.8) 12.8 3.3 (7.2) 3.6 (8) 1:9 APA M 11.2 E-7 5 0.4 (0.8) 12.8 1.4 (3.2) 1.8 (4) 1:4 APA M 4.4 E-8 5 0.7 (1.6) 12.8 2.9 (6.4) 3.6 (8) 1:4 APA M 9.6 E-9 N / A None 15 1.8 (4) 1.8 (4) 0:1 N / A 3.3 E- 10 N / A None 15 3.6 (8) 3.6 (8) 0:1 N / A 10.4 E- 11 25S 0.2 (0.4) 15 1.6 (3.6) 1.8 (4) 1:9 APA M 8.9 E- 12 25S 0.4 (0.8) 15 3.3 (7.2) 3.6 (8) 1:9 APA M 14.3 (5) Improved strength reported as % increase, relative to blank performance (Ring crush) SAPAM 1 (polymer in solution)

[0075] As shown in Test A, the additive composition using the average GPAM loading (e.g., 12.8% cationic) demonstrates compatibly increased resistance performance on an equal total dosage basis. Conversely, compositions using a low normal GPAM loading (e.g., 4.1% cationic) did not achieve the resistance performance levels as those using GPAM at 12.8% cationic or higher. As also shown, a relatively low proportion of APAM can be used to improve resistance performance, and higher molecular weight APAM provided higher resistance compared to lower molecular weight variants. In this test, no evident effect of APAM loading could be observed in terms of performance characteristics.

[0076] As further demonstrated in Test B, the additive composition Petition 870250109957, dated 01 / 12 / 2025, page 35 / 50 30 / 44 using the average GPAM loading (e.g., 12.8% cationic) provides comparably increased resistance performance on an equal total dosage basis. Conversely, compositions using a low normal GPAM loading (e.g., 4.1% cationic) did not achieve the resistance performance levels as those using 12.8% cationic GPAM or higher. As also shown, a relatively low APAM ratio (e.g., 1:6 and 1:9 APAM:GPAM ratios) can provide improved resistance performance. These effects are further supported by the results of Test C, which used a low normal GPAM loading (e.g., 4.1% cationic) in combination with APAM having a lower anionic loading. However, no resistance improvement comparable to the improvement on an equal total dosage basis using 4.1% cationic GPAM was achieved.

[0077] As shown in Test D, high-charge GPAM provided the additive composition with improved strength performance compared to compositions containing lower-charge GPAM. Surprisingly, additive compositions using 20.6% cationic GPAM increased strength performance compared to GPAM alone, even at the same total dosage. Improved performance was also achieved using combinations with a relatively low APAM to GPAM ratio, for example, 1:9.

[0078] As shown in Test E, using additive compositions with high and low charge APAM in combination with cationic GPAM at 12.8%, decreasing the proportion of APAM can be used to improve the resistance performance of the additive composition even when a low charge APAM is used. It is also shown that dispensed GPAM (i.e., GPAM 4) can be used in the additive composition and achieves adequate resistance performance when optimized according to the embodiments herein. Drainage performance

[0079] A vacuum drainage test was performed using a Dynamic Drainage Analyzer (DDA). The old corrugated container (OCC) was refined to a CSF of ~350 to 400 mL and then diluted with DI water to a consistency of 0.9%. Petition 870250109957, dated 01 / 12 / 2025, p. 36 / 50 31 / 44 diluted pulp was added calcium chloride (147 g per 1000 L), sodium bicarbonate (84 g per 1000 L), and sodium sulfate (added until the solution conductivity reached ~2000 μS / cm). The pH of the pulp was adjusted to 7 using concentrated sulfuric acid, followed by the addition of 2.5% by weight (dry basis) of oxidized starch (GPC D-28F). Drainage time was measured using a PulpEye Dynamic Drainage Analyzer 4. A 60-mesh sieve with a 95 mm cross-sectional filtration diameter was used. The analyzer applies a vacuum of 300 mbar and measures the time between vacuum application and the vacuum breakthrough point, or when air breaks through the fiber mat thickness. To perform the test, 750 mL of feed were loaded into the sample receptacle and the pulp was agitated. After 15 seconds of agitation, the polymeric additive was added to the agitated pulp slurry and agitation was continued for an additional 10 seconds.The instrument then stops the agitation, applies a vacuum, and records the pressure versus time, that is, to determine the amount of time it takes to reach the vacuum breakdown point.

[0080] Two drainage tests (Test F & Test G) were conducted according to the DDA procedure above. The specific parameters and results of the drainage tests are presented in the tables below. All drainage values ​​are reported as the % reduction in drainage time vs. blank. A negative value indicates that the drainage time was longer than the blank. For performance comparisons, the examples presented in each table were conducted at the same time, on the same feed. Table 7 - Dynamic Drainage Analysis - F-Test APAM GPAM Additive Composition Ex. Anionic (%) Dosage m kg / ton (lb / ton) Cationic (%) Dosage m kg / ton (lb / ton) Dosage m Total kg / ton (lb / ton) APAM:GP AM Order of Add. (1st) Best in Drainage (% of time) Petition 870250109957, dated 01 / 12 / 2025, page 37 / 50 32 / 44 (6) F- 1 N / A None at 12.8 2.7 (6) 2.7 (6) 0:1 N / A 22.5 F- 2 18 0.9 (2) 12.8 1.8 (4) 2.7 (6) 1:2 APAM -12.8 F- 3 18 0.7 (1.5) 12.8 2.0 (4.5) 2.7 (6) 1:3 APAM -9.3 F- 4 18 0.4 (0.86) 12.8 2.3 (5.14) 2.7 (6) 1:6 APAM 2.2 F- 5 18 0.3 (0.6) 12.8 2.4 (5.4) 2.7 (6) 1:9 APAM 7.9 F- 6 10 0.7 (1.5) 12.8 2.0 (4.5) 2.7 (6) 1:3 APAM -1.9 F- 7 25B 0.7 (1.5) 12.8 2.0 (4.5) 2.7 (6) 1:3 APAM -7.6 F- 8 N / A None at 1.8 (4.1) 2.7 (6) 2.7 (6) 0:1 N / A 17.8 F- 9 18 0.9 (2) 1.8 (4.1) 1.8 (4) 2.7 (6) 1:2 APAM -8.0 F- 10 18 0.7 (1.5) 1.8 (4.1) 2.0 (4.5) 2.7 (6) 1:3 APAM -8.3 F- 11 18 0.4 (0.86) 1.8 (4.1) 2.3 (5.14) 2.7 (6) 1:6 APAM -0.3 F- 12 18 0.3 (0.6) 1.8 (4.1) 2.4 (5.4) 2.7 (6) 1:9 APAM 1.9 F- 13 10 0.7 (1.5) 1.8 (4.1) 2.0 (4.5) 2.7 (6) 1:3 APAM -7.6 F- 25B 0.7 (1.5) 1.8 2.0 (4.5) 2.7 (6) 1:3 APAM -10.1 Petition 870250109957, dated 01 / 12 / 2025, page 38 / 50 33 / 44 (4.1)

[0081] (6)% Improvement in drainage time reported as % decrease, compared to white

[0082] B APAM 3 (granulated polymer) Table 8 - Dynamic Drainage Analysis - G-Test APAM GPAM Additive Composition Ex. Anionic (%) Dosage kg / ton (lb / ton) Cationic (%) Dosage kg / ton (lb / ton) Total Dosage kg / ton (lb / ton) APAM:GPAM Order of Add. (1st) Improvised Drainage (% time) (6) G-1 N / A None 1.8 (4.1) 2.7 (6) 2.7 (6) 0:1 N / A 19.4 G-2 N / A None 5.8 (12.8) 2.7 (6) 2.7 (6) 0:1 N / A 26.7 G-3 N / A None 9.3 (20.6) 2.7 (6) 2.7 (6) 0:1 N / A 36.6 G-4 25S 0.3 (0.6) 9.3 (20.6) 2.4 (5.4) 2.7 (6) 1:9 APAM 35.9 G-5 10 0.3 (0.6) 9.3 (20.6) 2.4 (5.4) 2.7 (6) 1:9 APAM 36.4 G-6 5 0.3 (0.6) 9.3 (20.6) 2.4 (5.4) 2.7 (6) 1:9 APAM 37.7 G-7 25S 0.3 (0.6) 9.3 (20.6) 2.4 (5.4) 2.7 (6) 1:9 GPAM 24.4 G-8 10 0.3 (0.6) 9.3 (20.6) 2.4 (5.4) 2.7 (6) 1:9 GPAM 29.9 G-9 5 0.3 (0.6) 9.3 (20.6) 2.4 (5.4) 2.7 (6) 1:9 GPAM 30.1 G- 10 25S 0.3 (0.6) 5.8 (12.8) 2.4 (5.4) 2.7 (6) 1:9 APAM 18,4 Petition 870250109957, dated 01 / 12 / 2025, page 39 / 50 34 / 44 G- 11 10 0.3 (0.6) 5.8 (12.8) 2.4 (5.4) 2.7 (6) 1:9 APAM 20.4 G- 12 5 0.3 (0.6) 5.8 (12.8) 2.4 (5.4) 2.7 (6) 1:9 APAM 21.6 G- 13 25S 0.3 (0.6) 5.8 (12.8) 2.4 (5.4) 2.7 (6) 1:9 GPAM 11.6 G- 14 10 0.3 (0.6) 5.8 (12.8) 2.4 (5.4) 2.7 (6) 1:9 GPAM 11.8 G- 15 5 0.3 (0.6) 5.8 (12.8) 2.4 (5,4) 2,7 (6) 1:9 GPAM 16,6

[0083] (6)% Improvement in drainage time reported as % decrease, compared to white SAPAM 1 (polymer in solution)

[0084] As shown in tests F to G, the use of APAM severely reduced the drainage performance of additive compositions using low and normal / medium loading of GPAMs (e.g., 4.1% and 12.8% cationic). However, lower proportions of APAM result in less of a negative effect on drainage, and the use of lower loading of APAM in the additive composition results in less of a negative effect on drainage. Notably, additive composition embodiments comprising high loading, high molecular weight GPAM provide stable (i.e., not reduced) drainage performance when APAM is used before GPAM.

[0085] As demonstrated in the example above, the additive composition comprising on-site combinations of GPAM and APAM with varying filler densities and molecular weights is optimized in OCC to maximize strength and minimize negative effects on drainage performance. The relative APAM:GPAM ratio in the additive composition is also optimized, along with the application procedure concerning the effects of the addition order for the GPAM and APAM resins used. Petition 870250109957, dated 01 / 12 / 2025, pages 40 / 50 35 / 44

[0086] As shown, significant resistance improvement is provided by the additive composition comprising APAM-GPAM combinations in a total dosage equal to that of GPAM alone. Although drainage may be negatively impacted, some combinations provide the additive composition with maintained drainage performance relative to GPAM alone. Other unexpected effects were also observed during the example tests reported above.

[0087] For example, it can be observed that drainage performance is almost always negatively affected by the use of APAM, even at low APAM:GPAM ratios, compared to the use of GPAM alone. A notable solution to this was found by applying the additive composition using a high filler, high molecular weight GPAM (i.e., GPAM 3) in a second addition step, following the application of the APAM component in a first addition step.

[0088] It has also been shown that increasing the cationic charge of GPAM resulted in increased resistance performance of the additive composition. Conversely, when drainage was negatively affected, reducing the APAM charge typically resulted in less of a negative effect (i.e., lower APAM charge reduced the observed reduction in drainage performance).

[0089] It was also found that increasing the molecular weight of APAM resulted in increased strength performance of the additive composition. This effect was also demonstrated with the use of APAM granules (i.e., APAMs 3 to 5), which typically comprise higher molecular weight resins and generally performed better than APAMs in the solution state of the same filler.

[0090] In specific implementations, a relatively low APAM to GPAM ratio has been shown to provide balanced performance in achieving improved strength and drainage performance. For example, an APAM:GPAM ratio of 1:9 is demonstrated in examples with good results.

[0091] It has also been shown that the order in which components are added when using additive composition improves performance, as well as being useful for adapting Petition 870250109957, dated 01 / 12 / 2025, page 41 / 50 36 / 44 selectively balances performance between strength and drainage. For example, the first application of APAM (i.e., before GPAM) resulted in better drainage performance, while the second application of APAM (i.e., after GPAM) resulted in better strength performance. However, it was surprisingly found that although the second application of APAM always negatively impacted drainage performance, the order of each addition of the APAM and GPAM components resulted in better strength performance than GPAM alone (i.e., compared with the same total dosage for GPAMs, with medium or high load). Repulpability Performance

[0092] Two paper tests (Test H & Test I) were conducted to prepare paper samples for repulping analysis. The specific parameters and results of the paper machine tests are presented in the tables below. Table 9 - Paper Test H APAM GPAM Additive Composition Ex. Anionic (%) Dosage m kg / ton (lb / ton) Cationic (%) Dosage m kg / ton (lb / ton) Dosage m Total kg / ton (lb / ton) APAM:GPA M Order of Add. (1a) H-1 N / A None a N / A None a None a N / AN / A H-2 N / A None a 12.8 2.7 (6) 2.7 (6) 0:1 N / A H-3 18 0.7 (1.5) 12.8 2.0 (4.5) 2.7 (6) 1:3 APAM H-4 18 0.4 (0.86) 12.8 2.3 (5.14) 2.7 (6) 1:6 APAM H-5 18 0.3 (0.6) 12.8 2.4 (5.4) 2.7 (6) 1:9 APAM Table 10 - Paper Test I APAM GPAM Additive composition Petition 870250109957, dated 01 / 12 / 2025, pages 42 / 50 37 / 44 Ex. Anionic (%) Dosage m kg / ton (lb / ton) Cationic (%) Dosage m kg / ton (lb / ton) Dosage m Total kg / ton (lb / ton) APAM:GPA M Order of Ad. (1a) I-1 N / A None to N / A None to None to N / A N / A I-2 N / A None to 20.6 2.7 (6) 2.7 (6) 0:1 N / A I-3 25S 0.3 (0.6) 20.6 2.4 (5.4) 2.7 (6) 1:9 APAM I-4 25S 0.3 (0.6) 20.6 2.4 (5.4) 2.7 (6) 1:9 GPAM

[0093] S APAM 1 (polymer in solution)

[0094] The repulping performance was evaluated using an index classification (The Brecht-Zippel method or Blue Glass Pulping Index) to determine the quality of the repulping fluid pulp at 15-minute intervals until fully repulped. Repulping was carried out using a repulping apparatus (Waring Blender, equipped with a glass jar, blade and jar cover) fitted with a temperature controller and a motor controller with a timer. Paper samples totaling approximately 18 grams were cut into square pieces of ~2.54 cm (1”). Approximately 342 grams of water were added to the blender jar such that the consistency of the final fluid pulp paste would be 5%. The water temperature was raised to 52°C (125°F). The paper pieces were added, allowed to soak for 5 minutes, and then repulped at a shear rate of 1500 rpm at 52°C (125°F) for 15 minutes.A spoonful of the fluid paste was removed, added to 100 mL of water in a plastic cup, mixed, and poured onto the top of a blue glass. The sample was then visually evaluated against a Brecht-Zippel Blue Glass Index standard and graded to an index point that most closely resembles the pulp sample, on a scale of 1 to 9 according to the index table below. Petition 870250109957, dated 01 / 12 / 2025, pages 43 / 50 38 / 44 Table 11 - Sample Evaluation Index No. Pulp Rejects (%) 1 41 2 25 3 15 4 5.5 5 2.5 6 1.2 7 0.25 8 0.10 9 0.05

[0095] Repulping was continued at 15-minute intervals until 120 minutes had elapsed or the fluid pulp was completely repulped (i.e., graded at index No. 9).

[0096] The results of the repulpability assessment, reported as the Index No. rating of each sample in the given time interval, are presented in the tables below: Table 12 - Repulping Analysis - H-Test Results Ex. 15 Min. 30 Min. 45 Min. 60 Min. H-1 9 - - - H-2 3 6 9 - H-3 3 6 9 - H-4 3 6 9 - H-5 2 5 8 9 Table 13 - Repulping Analysis - Test I Results Ex. 15 Min. 30 Min. 45 Min. 60 Min. 75 Min. 90 Min. Petition 870250109957, dated 01 / 12 / 2025, pages 44 / 50 39 / 44 I-1 9 - - - - - I-2 1 3 4 5 8 9 I-3 1 2 5 6 9 - I-4 1 3 4 5 8 9

[0097] The effect on repulpability of different APAM:GPAM ratios using cationic GPAM at 12.8% (GPAM 2) and anionic APAM at 18% (APAM 2) was evaluated in the H-test. Conventional additive compositions are known to have decreased repulpability, potentially due to the building of permanent wet strength through the incorporation of additives. As shown above, however, the compositions of the present embodiments showed increased strength and drainage performance without reducing the repulpability of paper prepared with them.

[0098] The effect on repulpability of different addition orders using 20.6% cationic GPAM (GPAM 3) and 25% anionic APAM (APAM 1, solution polymer) was evaluated in test I. In each case, the additive composition provided in any addition order maintained the repulpability of the GPAM component used alone.

[0099] At the dosages evaluated, the additive composition of the present embodiments provides superior adjustable properties of strength and drainage, without sacrificing repulpability.

[0100] Paper Machine Preparation - Commercial Feeding and White Water

[0101] A feedstock composed of OCC fibers was obtained from a commercial paper mill and dispersed in white water obtained from the same paper mill. The CSF was measured to be 550 mL. The conductivity of the water was measured to be 3542 uS / cm and the pH was measured to be 6.8. The stock was applied to the paper machine via an upper inlet box of the flow spreader (hydraulic) onto a flat table equipped with vacuum-assisted baffles to remove water and form a wet sheet. The wet sheet was then passed through two presses. Petition 870250109957, dated 01 / 12 / 2025, pages 45 / 50 40 / 44 single felt to mechanically remove water and densify the sheet. Final water removal (drying) is performed using electrically heated drying cans before being wound onto a core on the reel, targeting a base weight of 0.15 kg / m2 (93 lb / 3000 sq ft). Mechanical strength performance: J test

[0102] Ring crush was measured with a Crush Testing Machine, with the analysis performed according to the TAPPI T 822 method (e.g., om-16).

[0103] A paper machine test (Test J) was conducted according to the above procedure. The specific parameters and results of the paper machine test are presented in the table below. All strength values ​​are reported as % increase vs. blank, determined by the Ring Crush Test. Each example presented in the table was conducted at the same time, on the same feed. Table 14 - Paper Machine - J Test APAM GPAM Additive Composition Ex. Anionic (%) Dosage kg / ton (lb / ton) Cationic (%) Dosage kg / ton (lb / ton) Total Dosage kg / ton (lb / ton) APAM:GPAM Order of Add. (1a) Resistance Improvement (%)(5) J-1 N / A None 4.1 2.7 (6) 2.7 (6) 0:1 N / A 5.2 J-2 10 0.3 (0.6) 4.1 2.4 (5.4) 2.7 (6) 1:9 GPAM 9.6 J-3 18 0.3 (0.6) 4.1 2.4 (5.4) 2.7 (6) 1:9 GPAM 11.4 J-4 5 0.3 (0.6) 4.1 2.4 (5.4) 2.7 (6) 1:9 GPAM 5.2 J-5 N / A None 12.8 2.7 (6) 2.7 (6) 0:1 N / A 6.2 J-6 10 0.3 (0.6) 12.8 2.4 (5.4) 2.7 (6) 1:9 GPAM 4.7 J-7 18 0.3 (0.6) 12.8 2.4 (5.4) 2.7 (6) 1:9 GPAM 7.7 J-8 N / A None 20.6 2.7 (6) 2.7 (6) 0:1 N / A 5.9 J-9 10 0.3 (0.6) 20.6 2.4 (5.4) 2.7 (6) 1:9 GPAM 8.2 J-25S 0.3 (0.6) 20.6 2.4 (5.4) 2.7 (6) 1:9 GPAM 10.5 Petition 870250109957, dated 01 / 12 / 2025, pages 46 / 50 41 / 44 10

[0104] (5) )% Improvement in drainage time reported as % decrease, compared to blank SAPAM 1 (polymer in solution)

[0105] Several formulations of the additive composition were evaluated in the J-test, which was conducted using commercial feed and white water from a commercial paper mill in order to more closely simulate commercial conditions. In particular, commercial feed has higher amounts of soluble lignin, higher conductivity, different saline mixtures and expected amounts of anionic waste, each of which influences additive performance.

[0106] As shown, the additive composition demonstrated improved strength performance compared to the controls, even under difficult feeding conditions. The improved performance was indicated with a higher APAM loading, which was not as evident from tests conducted on synthetic feed. As such, the present embodiments demonstrate adjustable performance across a wide range of conditions, where the loading and / or increased molecular weight of the APAM component can be selected to maintain improved performance under various feeding requirements. Furthermore, it was also demonstrated that the combination of specific components in the additive composition provides superior strength performance compared to GPAM used alone at the same GPAM dosage.Consequently, the present embodiments provide a solution for applications requiring the strength, drainage, and repulpability benefits of additives, but which are limited by cationic charge due to charge inversion and operability issues. The present compositions provide a charge balancing solution, which is believed to allow for higher overall GPAM dosages, capable of improving strength and drainage without sacrificing repulpability or operability.

[0107] In view of the above, the additive composition can be readily designed for use in enhancing machine productivity. Additionally, the additive composition can be used to provide good dry strength. In view of the adjustability Petition 870250109957, dated 01 / 12 / 2025, pages 47 / 50 42 / 44 particular of the additive composition, however, it will be easily understood that the specific combination of the relatively high molecular weight and medium to high charge of GPAM combined with the relatively high molecular weight and low charge of APAM provides the additive composition with unique adjustability to achieve improved and balanced performance characteristics that can be exploited to prepare numerous paper products.

[0108] Although at least one exemplary embodiment has been presented in the preceding detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or embodiments are merely examples and are not intended to limit the scope, applicability, or configuration in any way. Rather, the preceding detailed description will provide those skilled in the art with a convenient roadmap for implementing an exemplary embodiment. It is assumed that various changes can be made to the function and arrangement of elements described in an exemplary embodiment without diverging from the scope as presented in the appended claims. Furthermore, all combinations of components, compositions, method steps, formulation steps, etc.The aforementioned terms are hereby expressly considered for use herein in various, non-limiting ways, even if such combinations are not expressly described in the same or similar paragraphs.

[0109] With respect to any Markush groups used herein to describe particular features or aspects of various embodiments, different, special and / or unexpected results may be obtained from each member of the respective Markush group independently of all other Markush members. Each member of a Markush group may be used individually and / or in combination and provide adequate support for specific embodiments within the scope of the appended claims.

[0110] Furthermore, any ranges and subranges used in the description of the various embodiments of the present invention independently and collectively fall within the scope of the appended claims and are understood to describe and Petition 870250109957, dated 01 / 12 / 2025, pp. 48 / 50 43 / 44 consider all ranges including integer and / or fractional values ​​thereof, even if such values ​​are not expressly described herein. A person skilled in the art will readily recognize that the ranges and subranges enumerated herein sufficiently describe and enable various embodiments of the present invention, and such ranges and subranges may be further delineated into relevant halves, thirds, quarters, fifths, and so forth. As just one example, a range “from 0.1 to 0.9” may be further delineated into a lower third, i.e., from 0.1 to 0.3, an intermediate third, i.e., from 0.4 to 0.6, and an upper third, i.e., from 0.7 to 0.9, which individually and collectively are within the scope of the appended claims and may be used individually and / or collectively and provide adequate support for the specific embodiments within the scope of the appended claims.Furthermore, with respect to language that defines or modifies a range, such as “at least,” “greater than,” “less than,” “not more than,” and the like, it should be understood that such language includes subranges and / or an upper or lower limit. As another example, a range of “at least 10” inherently includes a subrange of at least 10 to 35, a subrange of at least 10 to 25, a subrange of 25 to 35, and so on, and each subrange may be used individually and / or collectively and provides adequate support for specific embodiments within the scope of the appended claims. An individual number within a described range may be used and provides adequate support for specific embodiments within the scope of the appended claims.For example, a range “from 1 to 9” includes several individual whole numbers, such as 3, as well as individual numbers including a decimal point (or fraction), such as 4.1, which can be used and provide adequate support for specific embodiments within the scope of the appended claims. Finally, it will be understood that the term “about” with respect to any of the particular numbers and ranges described herein is used to designate values ​​within the standard error, equivalent function, effectiveness, final load, etc., as understood by those skilled in the art with conventional techniques and processes relevant to the formulation and / or utilization of compounds and compositions such as those described herein. Petition 870250109957, dated 01 / 12 / 2025, pp. 49 / 50 44 / 44 such, the term “about” may designate a value within 10, alternatively within 5, alternatively within 1, alternatively within 0.5, alternatively within 0.1% of the enumerated value or range.

[0111] Although the present description has been described with respect to its particular embodiments, it is evident that numerous other forms and modifications will be obvious to those skilled in the art. The appended claims and this description are generally to be interpreted as encompassing all such obvious forms and modifications, which are within the true scope of the present description. Petition 870250109957, dated 01 / 12 / 2025, p. 50 / 50

Claims

1 / 4 CLAIMS 1. An optimized additive composition for drainage in papermaking, characterized in that it comprises: an aqueous medium; a glyoxylated polyacrylamide (GPAM) resin having a weighted average molecular weight (Mw) of at least about 5 MDa and a cationic monomer content of at least about 4 mol%, alternatively at least about 10 mol%; and an anionic polyacrylamide (APAM) resin having a weighted average molecular weight (Mw) of at least about 0.25 MDa and an anionic monomer content of up to about 25 mol%, wherein the APAM resin and the GPAM resin are used in a w / w ratio of about 1:99 to about 1:2 (APAM:GPAM), alternatively from about 1:20 to about 1:5 (APAM:GPAM), based on the total weight of the APAM resin and the GPAM resin.

2. Additive composition according to claim 1,characterized in that the glyoxalized polyacrylamide resin GPAM comprises the reaction product of (A) a cationic acrylamide prepolymer (CPAM) and (B) glyoxal in an aqueous medium, and wherein the CPAM prepolymer (A) and glyoxal (B) are reacted in a dry weight (w / w) ratio of about 85:30 to about 95:5 (A):(B), alternatively about 75:25 to about 90:10, alternatively about 85:15 (A):(B).

3. Additive composition according to claim 1, characterized in that the CPAM prepolymer (A) comprises the reaction product of: (A1) an acrylamide monomer (AM); (A2) a cationic monomer; and (A3) optionally, one or more additional ethylenically unsaturated monomers; and wherein the CPAM prepolymer (A) comprises at least about 10 mol%, alternatively at least about 12 mol%, of units of Petition 870250090404, dated 03 / 10 / 2025,Page 23 / 28 2 / 4 cationic monomer derivatives of the cationic monomer (A2).

4. Additive composition according to claim 3, characterized in that the AM monomer (A1), the cationic monomer (A2) and optionally the additional ethylenically unsaturated monomers (A3) are reacted in the presence of a chain transfer agent.

5. Additive composition according to claim 3, characterized in that: (i) the AM monomer (A1) comprises acrylamide; (ii) the cationic monomer (A2) comprises diallyldimethylammonium chloride (DADMAC); (iii) one or more additional ethylenically unsaturated monomers (A3), when present, are selected from styrenes, alkyl acrylates and vinyl acetates; or (iv) any combination of (i) to (iii).

6. Additive composition according to claim 1, characterized in that the glyoxylated polyacrylamide (GPAM) resin comprises: (i) a weighted average molecular weight (Mw) of at least about 6,alternatively at least about 8, alternatively at least about 10 MDa; (ii) a cationic monomer content of at least about 12, alternatively at least about 14, alternatively at least about 16, alternatively at least about 18, alternatively at least about 20 mol%; or (iii) both (i) and (ii).

7. Additive composition according to claim 1, characterized in that the anionic polyacrylamide resin (APAM) comprises: (i) a weighted average molecular weight (Mw) of at least about 0.5, alternatively at least about 1, alternatively at least about 2 MDa; (ii) an anionic monomer content of less than about 20, Petition 870250090404, dated 03 / 10 / 2025, p. 24 / 28 3 / 4 alternatively less than about 18, alternatively less than about 15, alternatively less than about 12, alternatively less than about 10, alternatively less than about 8, alternatively less than about 8,alternatively less than about 6 mol%; or (iii) both (i) and (ii).

8. Additive composition according to any one of claims 1 to 7, characterized in that the additive composition is optimized for drainage performance by selecting the relative proportion of APAM resin and GPAM resin used based on: (i) weighted average molecular weight (Mw) of glyoxylated polyacrylamide resin (GPAM); (ii) cationic monomer content of glyoxylated polyacrylamide resin (GPAM); (iii) weighted average molecular weight (Mw) of anionic polyacrylamide resin (APAM); (iv) anionic monomer content of anionic polyacrylamide resin (APAM); or (v) any combination of (i) to (iv) such that the additive composition exhibits drainage performance greater than that of APAM resin used alone and substantially not less than the drainage performance exhibited without the use of either APAM resin or GPAM resin,as determined substantially under the same conditions by the vacuum drainage test performed after application to a cellulose pulp suspension.

9. Method for preparing an optimized additive composition for drainage in papermaking, characterized in that it comprises: preparing in an aqueous medium a glyoxylated polyacrylamide resin (GPAM) having a weighted average molecular weight (Mw) of at least about 5 MDa and a cationic monomer content of at least about 4 mol%, alternatively at least about 10 mol%; Petition 870250090404, dated 03 / 10 / 2025, page 25 / 28 4 / 4 providing an anionic polyacrylamide resin (APAM) having a weighted average molecular weight (Mw) of at least about 0.25 MDa and an anionic monomer content of up to about 25 mol%; and combine anionic polyacrylamide resin (APAM) and glyoxylated polyacrylamide resin (GPAM) in a w / w ratio of about 1:99 to about 1:2 (APAM:GPAM),Alternatively, approximately 1:20 to approximately 1:5 (APAM:GPAM), based on the total weight of the APAM resin and the GPAM resin, thus giving the additive composition.

10. Process for forming paper, characterized in that said process comprises: (1) providing an aqueous suspension of cellulosic fibers; (2) to form the cellulosic fibers in a sheet; (3) applying an additive composition comprising an anionic polyacrylamide resin (APAM) and a glyoxylated polyacrylamide resin (GPAM) to a sheet surface, wherein the additive composition is the additive composition according to claim 1; and (4) drying the sheet to produce a paper. Petition 870250090404, dated 10 / 03 / 2025, pp. 26 / 28